Comparison of Helicopter Engines

John Schenderlein, Tyler Clayton Turboshafts...What are they? • Needed for high power in a small envelope

• Very similar to turboprops

• many turboshafts derived from turboprop engines

• However,

• exhaust is not used to propel

• propeller load is applied to the airframe

• Began ~1950s Main Uses

• Helicopters

• APUs

• Marine Vehicles CH-53 Super Stallion

• Tanks

• Motorcycles

• industrial power generation M1 Abrams

MTT Superbike Major Players in the Market Turbomeca

• French Manufacturer for small/medium turboshafts (500-3000 shp)

• 18000+ in operation

• Most popular engine: Arriel (600-1000 shp)

• 30 variants

• 245 lbs

• SFC = 0.57

• 1 axial/1 Centrifugal compressor (PR ~9)

• 2 HPT/1 FPT turbine Turbomeca

• Newest Engine: Arrano (2018)

• 10-15% increase SFC

• new thermodynamic core & use of variable pitch inlet guide blades

• Uses additive manufacturing for injectors Rolls-Royce

• Most popular engine: M250 Series

• inherited from Allison Engine Company (1990s)

• 31000+ produced (50%+ in operation)

• 450-715 shp

• 160-275 lbs

• 4-6 axial/1 centrifugal compressor (PR 6-9)

• 2 HPT/2 FPT

• Also used on the MTT Superbike RQ-8A Fire Scout Allison Engines (Rolls Royce)

• Most noteable engine: T406

• Build specifically for the V-22 Osprey

• 6150 shp

• 971 lbs (6.33 p/w)

• 14 axial compressor stages! Pratt and Whitney Canada • Canadian based subsidiary of PW

• focuses on smaller aircraft engines

• Majority of their engines based on the PT6 turboprop

• PT6B/C series and the PT6T Twin-Pac (1000-2000 shp)

• 3-4 axial/1 centrifugal

• SFC 0.59

• 2 HPT/2 FPT

• PT6T uses two PT6A engines combining gearbox

• Popular among Bell 412/212 helicopters GE Aviation • Entered aviation industry w/ production of super/turbochargers

• First turboshaft: T58

• 1250-1870 shp

• SFC = .39

• 10 axial (PR 8.3) & 2 HPT/1 FPT

• Used on Marine One

• Major seller today: T700/CT7

• 1900-2600 shp

• 5 axial/1 centrifugal (PR18)

• AH-64 Apache engine GE Aviation Con’t

• Newest Engine: GE38 (upgrade to the T64)

• Designed for heavy lifting

• 7500 shp (57% increase)

• SFC: ~.39 (18% increase)

• 63% fewer parts

• sand tolerant/corrosion resistant compressor(TiN coating)

• improved inlet particle separators w/ CFD http://tx.technion.ac.il/~jetlab/9aijes/2%20- • CMC’s used in turbine %20Helicopter%20Engine%20Technology%20Pit ch_v6.pdf • Fills a gap in the marketnot many engines 6000+ to 10000 shp range Textron Lycoming

• Put the first turbine engine into a helicopter: UH-1

• Now makes the powerful T55 for the US Chinook twin rotor helicopter Turboshafts of a Different Era

• Soloviev Design Bureau

• Responsible for one of the most powerful turboshaft engines ever (D-136)

• Klimov Experimental Design Bureau

• Produced the TV3-117 engine

• Powered 95% of Russian Helicopters - used throughout the developing world Conclusions & Comparisons

• Almost all use a 2 spool design with usually 2 HPT and 2 FPT

• exceptions:

• smaller use 1 HPT/1 FPT

• large use 2 HPT/3 FPT

• Most use a combo of Axial/Centrifugal compressors

• SFC

• New engines: 0.39-0.42 kg/kW/hr

• Older engine: 0.5-0.6 kg/kW/hr